Environmental-aspect-Kurunov

OJSC “NOVOLIPETSK STEEL”
ENVIRONMENTAL ASPECT OF INDUSTRIAL
TECHNOLOGIES FOR RECYCLING OF FEAND ZN-CONTAINING SLUDGE AND DUST
Speaker:
2011
Ivan Kurunov – Doctor of
Technical Sciences
The production of one ton of
steel requires spending almost
20 GJ of energy and is
accopmpanied by the
emission of 1.7 t of СО2 into
the atmosphere. In addition
20-25 kg of sludges and dust
are generated, containing up
to 60% of iron in the form of
oxides and up to 2.5% of zink.
In blast furnace iron production 5-15 kg
of sludges is generated, where, apart
from iron and carbon (25-30%), up to
1.5% of zink is contained. The recycling
of this technologically generated raw
material will be a solution to one of the
most important environmental and
economical tasks.
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We reviewed four industrial process routes for recycling of iron
and zink containing sludges and dusts with the obtaining of iron
as a final product and commodity output with high content of
zink.
For all the routes СО2 through out emission was calculated at the
recycling of BOF and BF iron and zink containing sludges for
iron producer of an integrated type in the amount of 600
thousand t/y.
The first stage for all these
technologies is usually a
pelletizing of the sludges
by the method of hard
extrusion which makes
able to obtain sturdy
cylindrical briquettes 20-30
mm in diameter and 40-80
mm in length.
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4
5
Melting briquettes in a blast furnace
(DK Recycling process)
6
Metallization of briquettes in a ring chamber furnace with
rotating floor (Fastmet, Rediron) and the use of the received
DRI in blast furnace process
7
Metallization of briquettes by Waeltz process and the use of
the resulting DRI in blast furnace process
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Melting of briquettes in OxyCup cupola
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The method for calculation of through out consumption of
fuel and emission of СО2
At the calculation of through out
consumption of fuel and emission
of СО2 the following fuel
consumption figures were taken
into account:
• coke production,
• sinter production,
• pellets calcination,
• production of DRI out of
sludges,
• oxygen production,
• iron production in a blast
furnace,
• ironmaking in a cupola.
Consumption of fuel and oxygen in blast
furnace process for different variants was
evaluated by computer simulation model with
the application of a balance mathematical
model of a blast furnace process, constructed
with the use the operational line of A. Rist.
The fuel consumption in OxyCup process was
assumed according to the published data.
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Consumption of carbon and emission of СО2
in ironmaking according to the variants, kg/t
Blast furnace burden components
Points of carbon
consumption, kg/t of hot
metal
Sinter Production output
Pellet production
Production DRI *
Briquette composition
DRI composition
Coke**
Natural gas
Oxygen content in
blast***
Carbon consumed
Emission of СО2
the
Sinter
and pellet
Briquettes
and pellets
DRI
(Fastmet),
sinter,
pellets
DRI
(Waeltz)
sinter,
pellets
Process
OXYCUP
65
2,5
–
–
–
315
56
–
15
–
108
–
277
28
14
13
71
–
4,5
285
50
14
13
393
–
4,5
285
50
–
–
–
262,5
11,5
–
9
9
39
451,0
428,0
446,5
768,5
564,5
1654
1569
1674
2818
2070
263
–
* Heating up to 1300 °С, direct iron reduction, overall heat losses.
**Less carbon, which was transfered into iron.
*** Assuming 1787 kkal/m3 О2 or С/m3 О2.
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CONCLUSION
Of all industrially used technologies for recycling of
iron and zink containing sludges and dusts the minimum
fuel consumption per ton of iron, made using them, and
the minimum СО2 emission is provided by: the blast
furnace process recycling of briquettes from these
sludges and blast furnace processing of DRI which was
produced by metallization of such briquettes by Fastmet or
Rediron processes. Through out emission of СО2 in
OXYCUP process and in BF process with the use of DRI,
produced by Waeltz process, 1.3 and 1.8 times higher, than
during the melting of the briquettes in the blast furnace.
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Thank you
for your attention!